protected static void AssertTransitions(IReadOnlyNfa <string, char> nfa, string from, char on, string[] tos)
{
var expectedTos = tos.ToHashSet();
var gotTos = nfa.GetTransitions(from, on);
Assert.True(expectedTos.SetEquals(gotTos));
}
protected static void AssertTransitions(IReadOnlyNfa <StateSet <string>, char> nfa, string from, char on, string[] tos)
{
var fromSet = ParseStateSet(from);
var toSet = tos.Select(ParseStateSet).ToHashSet();
var gotTos = nfa.GetTransitions(fromSet, on);
Assert.True(toSet.SetEquals(gotTos));
}
/// <summary>
/// Implements <see cref="IReadOnlyFiniteAutomaton{TState, TSymbol}.Accepts(IEnumerable{TSymbol})"/> for NFAs.
/// </summary>
/// <typeparam name="TState">The state type.</typeparam>
/// <typeparam name="TSymbol">The symbol type.</typeparam>
/// <param name="nfa">The NFA to check acceptance on.</param>
/// <param name="input">The input to check acceptance for.</param>
/// <returns>True, if the <paramref name="input"/> is accepted by <paramref name="nfa"/>.</returns>
public static bool Accepts <TState, TSymbol>(IReadOnlyNfa <TState, TSymbol> nfa, IEnumerable <TSymbol> input)
{
var currentState = new StateSet <TState>(nfa.InitialStates, nfa.StateComparer);
foreach (var symbol in input)
{
currentState = nfa.GetTransitions(currentState, symbol);
if (currentState.Count == 0)
{
return(false);
}
}
return(currentState.Overlaps(nfa.AcceptingStates));
}
/// <summary>
/// Gets all transitions that are valid from a set of states on an input.
/// </summary>
/// <typeparam name="TState">The state type.</typeparam>
/// <typeparam name="TSymbol">The symbol type.</typeparam>
/// <param name="nfa">The NFA to get the transitions for.</param>
/// <param name="from">The set of states to transition from.</param>
/// <param name="on">The symbol to transition on.</param>
/// <returns>The set of states that are valid from the starting set on the input.</returns>
public static StateSet <TState> GetTransitions <TState, TSymbol>(
this IReadOnlyNfa <TState, TSymbol> nfa,
StateSet <TState> from,
TSymbol on) => new(from.SelectMany(s => nfa.GetTransitions(s, on)), nfa.StateComparer);
